Flexible duct used for transfer of heated or cooled air or other gases is typically designed for low-pressure usage, e.g. about 3 to 5 inches of water pressure. The duct is normally composed of an inner liner reinforced by a helical strand as of metal or plastic, a thick layer of flexible insulation such as fibrous glass around the liner, the insulation being surrounded by a flexible plastic, i.e. polymeric, jacket. As is well known, shipping, handling and storage costs and convenience are substantially improved by axially compressing the flexible duct into a small container, typically an elongated box, having a length only a small fraction of the initial hose length in its free state. One problem in particular relates to maintaining a length of packaged length of duct in its compressed state while the container is being loaded and closed for transport.
One technique employs a mechanical retaining tool to temporarily engage the compressed duct. This tool has prongs which are inserted through openings in a wall of the container, near the end through which the duct was admitted, so that the prongs engage the end of the compressed duct and physically hold the compressed duct in place until the open end of the container is closed. The tool is then withdrawn and the compressed duct is free to expand as far as the newly closed end of the box. This technique requires that special tooling must be provided to cut openings for the prongs into the blank from which the box is made. In addition, the presence of holes in the container can lead to contamination of the duct during transport or storage. Further, the formation of the holes in the container add to the cost of the container.
Therefore, a need exists for a packaging restraint and container that can retain a longitudinally compressed article, without requiring special manufacturing considerations. The need also exists for a container that can be readily manufactured. A further need exists for a container that can effectively seal the compressed article.